Hampshire County Council said the homes in Petersfield, Lyndhurst, Basingstoke and Romsey had become unsuitable to meet the needs of older people.

Richard Bambridge from union Unite said around 100 "frail" elderly residents would be "effectively evicted".

The council said a three month consultation would begin on Monday to discuss alternative means of care and accommodation.

Bulmer House in Petersfield, Cranleigh Paddock in Lyndhurst. Deeside in Basingstoke and Nightingale Lodge in Romsey could close.

The day centre at Cranleigh Paddock is also under threat.

The council said the homes had become unsuitable because of "narrow corridors, insufficient space for care equipment and shared toilet facilities".

Councillor Anna McNair Scott, executive member for Adult Social Care, said it would be "a difficult time" for the residents, their families and staff but that it would be supporting them through the process.

Mr Bambridge said it would be difficult for the elderly residents, "particularly those with dementia", to "up and move".

In September the council also earmarked three care homes - Addenbrooke in Gosport, Cornerways in Winchester and Thurlston House in Fleet - for closure once residents had found alternative accommodation.